Question

我在MSSQL中有以下数据：

declare @TEMP table (Period int, Color varchar(20), Rate int)
insert into @TEMP values(201601, 'Blue', 10)
insert into @TEMP values(201602, 'Blue', 10)
insert into @TEMP values(201603, 'Blue', 11)
insert into @TEMP values(201604, 'Red',  11)
insert into @TEMP values(201605, 'Red',  12)
insert into @TEMP values(201606, 'Blue', 13)
insert into @TEMP values(201607, 'Blue', 13)
insert into @TEMP values(201608, 'Blue', 14)
insert into @TEMP values(201609, 'Blue', 14)
insert into @TEMP values(201610, 'Blue', 14)
insert into @TEMP values(201611, 'Blue', 14)
insert into @TEMP values(201612, 'Blue', 14)

SELECT * FROM @TEMP

我想按照颜色进行分组，同时保持“时间顺序”。因此，前3个蓝色记录将独立于最后7个蓝色记录进行分组。最后，我想选择组中的“最新”行。

输出结果为：

    Period  |   Color   |   Rate
    ------  |   -----   |   ----
    201603  |   Blue    |   11
    201605  |   Red     |   12
    201612  |   Blue    |   14
    ------  |   -----   |   ----

Answer 1

由于窗口功能，我希望您使用的是某些较新版本的SQL Server。

以下是解决方案：

;with x as (
    select *, case when lag(color) over(order by period) = color then 0 else 1 end as g
    from @temp
),
y as (
    select *, sum(g) over(order by period) gg
    from x
),
z as (
    select *, row_number() over(partition by gg order by period desc) rn
    from y
)
select period, color, rate from z where rn = 1

分组并选择关于订单的最后价值

1 个答案: